I'll tack on the starting positions where units are stuck in the peanut gallery of a level 2 without access to lower levels or sometimes any other hexes. This happens to non-flyers in palace fights every so often. Managing to conserve mercs until the last fight only to have them neutralized on turn 1 is problematic. It's like the mercs became cats stuck up trees and need the fire department.

This has been fixed, and the fix will appear in the next release.
The "peanut gallery" problem should also be fixed.

Note, however:
It is possible that, depending on the map size, realm defenders (AI and invaders) may not be able to deploy all allies - in this case, the allies won't be present for the battle.
Realm attackers (humans) will always get all of their allies, even if it means they get an uncounterable strike on an enemy wizard (although the game will always avoid this where possible).
The game will still deploy to the peanut gallery if no other deployment positions are available.